1. Field of the Invention
The present invention is related to a vehicle navigation system, in particular, to a technique for upgrade of a vehicle navigation system.
2. Description of the Related Art
Vehicle navigation systems are provided with storage devices containing navigation software programs and map data. A hard disk drive is a typical storage device used in a vehicle navigation system. A navigation system with a built-in hard disk drive uses a navigation program and map data stored in a hard disk drive to navigate a vehicle to a destination.
Some drawbacks are in the navigation system with such a built-in hard disk drive. For the upgrade of the navigation system with a built-in hard disk drive, the hard disk drive must be detached, the navigation program and the map data stored in the hard disk drive must be upgraded, and the hard disk drive must be attached to the system again. Therefore, one of the drawbacks is in that the navigation system cannot be used during upgrade of the navigation program and the map data. Also, this upgrade procedure undesirably requires the user to hand over the vehicle to a dealer to have the hard disk drive updated.
Therefore, a need exists to provide a technique for effectively shortening the duration for the update.
An optical disk drive, such as a DVD-ROM drive, is another a typical storage device used in a vehicle navigation system. The navigation system with such a built-in DVD-ROM drive uses a navigation program and map data stored in a DVD-ROM to navigate a vehicle to a destination. Upgrading a navigation system with a built-in DVD-ROM drive can be achieved by replacing DVD-ROM to update the navigation program and map data. Therefore, the navigation system with the built-in DVD-ROM drive is superior to that with the built-in hard disk drive in necessary duration for the upgrade. Nevertheless, the DVD-ROM drive is inferior to the hard disk drive in access time, and this undesirably leads to a slow operation speed of the system. Therefore, a navigation system desirably operates using a hard disk drive to improve operation speed.
Navigation systems provided with both a hard disk drive and a DVD-ROM drive are disclosed in Japanese Laid Open Patent Applications No. 2001-133273 and 2001-165671. The disclosed navigation systems transfer map data stored in a DVD-ROM to a hard disk drive, and executes vehicle navigation using the map data transferred to the hard disk drive. These navigation systems allow users to use another DVD-ROM during the vehicle navigation.
Japanese Laid Open Patent Application No. 2000-251396 discloses an in-vehicle information processing unit for achieving reliable data write into a hard disk drive.